Method of and means for treating solids



C. l. HANEY METHOD OF AND MEANS FOR TREATING SOLIDS April 30, 1935.

2 Sheets-$heet 1 Filed Dec. 9, 1930 INVENTOR Clifford LHcme 1 BY mm W ATTORNEY5 April 30, 1935. c. I. HANEY 1,999,411

METHOD OF AND MEANS FOR TREATING SOLIDS Filed Dec. 9, 1950 2 Sheets-Sheet 2 I v '|i \fi o 0' J 2 Q E u m y II I o) INVENTOR go g} fi clh fordLHane/g i BY gw km ATTORNEYS Patented Apr. 30, 1935 a 1,999,411

UNITED STATES PATENT OFFICE 1,999,411 rmrnon or AND MEANS FOR rename soups Cliflord .I. Haney, 'Drummondville, Quebec, Canada, assignor to Celanese Corporation of America, a corporation of Delaware Application December 9, 1930, Serial No. 501,017 6 Claims. (Cl. 259-9) Thisinvention relates tomethod of and means of particles, particularly in the form of pari'or treating solidmaterials with liquids in a ticles of varying size. continuous manne The solid material may be subjected to the An object of my invention is to provide means action of any treating liquid, such as water for for continuously treating solid material in the washing, or the treating liquid may have a chemform of particles of difierent sizes with a treating ical or physical action thereon and may be in liquid. A further object of my invention is to the form of chemical liquids or aqueo solutions provide means for continuously washing celluof chemicals. lose acetate which has been precipitated from a For illustration of one mode of carrying out solution in acetic acid, whereby the resulting this invention, reference is had to the accomm 0 washed liquors are of high'acid concentration panying drawings which show a form of appaand the cellulose acetate is washed substantially ratus for removing excess acid from and washing free of acetic'acid. Other objects of this invencellulose acetateas formed by the p c p n tion will appear from the following detailed deof a solution of cellulose acetate in acetic acid by scription. v the addition of water to an acetylation mixture. u

The present method of washing cellulose ace- Fig. 1 shows a front elevation of the assembly tate that has been precipitated from its solution of apparatus including the supply tank, the in acetic acid is by a batch method. This batch drainer and the washer, method requires a large number of vats, centriiu- Fig. 2 is a vertical cross-section of the drainer, gals and other apparatus, and because of the Fig. 3 is an and elevation partly in section of so great amount of handling of material involved, the drainer,

the labor cost is quite high. Moreover the acetic Fig. 4 is a vertical cross-section of the washer acid is so diluted by washing with water in the taken along the line 4-4 of Fig. 6, batch method, that the cost of concentrating and I Fig. 5 isan end elevation, partly in section, of recovering the acetic acid is very high. the washer. u

Cellulose acetate, precipitated from its solution Fig. 6 is a plan view 0 the washer, and in acetic acid, often varies greatly from charge Fig. 7 is a cross-section of the washer taken to charge and is in a great variety of forms. The along the line 1-1 of Fig. 6. particle sizes often run from the dimension of The assembly of the apparatus shown on the dust to coarse pieces, 5 or 6" long. It is theredrawings includes a supply tank I for the mix- 30 tom quite diflicult to provide means for washing ture of cellulose acetate and diluted acetic acid, a

this material in a continuous manner, especially conduit 2 for conducting the mixture tothe drainasthc difiusion of the acid from the precipitated ing device 3, and chute I for conducting the cellulose acetate is not rapid during washing. drained cellulose acetate from the drainer I to Ihave found that cellulose acetate or other solid the washer 5. I 85 material in particle or fibre form may be treated All the parts of the apparatus may be made of with a liquid in a continuous manner, by causing wood, or they may be made of copper, bronze, the same to pass through a series of cells or comstainless steel, aluminum, in 'nel metal or other partments by means of propelling paddles, while id resisting materials. 40 0 11 8 the t t n liq i to ow in collnter- Referring to Figs. 2 and 3, the drainer 3 has a 0 current direction hr h u h c shaft 6 rotating therein, which shaft preferably In accordance with my invention, I treat a projects through the washer 30 t t; t t solid material with a treating liquid in a condrainer and the washer maybeopemted'together "mmus manner by using the material On the shaft 0 in the drainer, agitating arms 1 to pass continuously through a series of cells by suitable propelling means while causing the are mounted for stirring the material contained 16 therein. Near the exit end for the cellulose acetate mi? gt g gg m an opposite direction of the drainer, arms 8 are mounted on the shaft While this invention is of particular importance and these arms carry conveying padldles the in the treatment of cellulose acetate or other races of which eferaplymake an m e or cellulose esters which been 30 the rear wall 01 the drainer; from the solutions in which they were formed, the cellulose acetate material which is Picked up it is applicable to the treatment of other mateby the paddles ltends to slide down the opening rials such as cellulose nitrate, cellulose ethers and II in such wall into the chute l. The paddles l in fact any other solid material that is in the form are spaced somewhat from the wall I. to permit 55 the drainage of liquor from the cellulose acetate before it is dropped into the chute l.

The drainer 2 is provided with a sloping bottom, the lower part of which is in the form of spaced slats or bars l2, or in 'the form of a foraminous or perforated material. The liquor that drains from the cellulose acetate through the slats or bars I2 is caught in the receptacle H, from which it may be conducted to any desired storage or treating device.

Referring to Figs. 4 to 7, the washer 5 is divided into a series of compartments or cells ll of any desired number (9 are shown on the drawings) by means of the partitions I, one side I. of which is higher than the other side H. The upper edges of the partitions I! are preferably cut at an angle as shown in the drawings.

Mounted on the rotating shaft 2 are a series of arms H which carry paddle arms |2, the faces of which are preferably set at an angle of about to the direction of travel and which are adapted to cause the cellulose acetate to move across the compartments or cells M.

Near the partitions 'li, arms 2|! are mounted on the rotating shaft 2, one arm being provided in each cell It. Upon these arms 22, wedge-shaped paddles 2| are fixed, one face of such paddle being so positioned, that it makes an angle of about 30 with the plane of the partitions, so that as the paddles pass through the mixture of cellulose acetate and liquor in the cells, they lift some of the cellulose acetate above the liquid level, and the cellulose acetate so caught slips down the face of the paddle over the angular edge of the partition II when the lower edge of the paddle comes above the upper edge of the partition.

To permit the drainage of adhering liquor from the cellulose acetate, the paddles 2| are spaced somewhat from the partition l5, so that as the cellulose acetate is lifted by the paddles 2| above the liquid level, practically all of the free liquor drains away before the upper edge of the partition is reached. By means of this arrangement, the cellulose acetate acts as its own draining screen, and the greatest problem of a continuous washing scheme for such product, which contains particles of all sizes, is overcome.

Water or any other desired washing liquid is introduced through the inlet 22 and the liquor is withdrawn through the outlet 22, while the cellulose acetate material passes in a counter-current direction, entering by the chute 4 and leaving by chute 24. In order to permit the flow of liquid in the manner indicated, the height of the partitions l5 progressively decreases to a slight extent from the end where the liquid enters by pipe 22 to the end where the liquor leaves by pipe 22.

The following is a specific example, which is in no way limitative, of a method of draining and washing cellulose acetate which has been precipitated by the addition of water to an acetylation mixture comprising a solution of cellulose acetate in acetic acid.

The mixture of precipitated cellulose and acetic acid which is of about 40 to 45% concentration is passed from the vessel to the drainer 2, wherein the free acid liquor drains through the spaced slats or bars l2, into the receptacle l2 from which it may be drawn of! tobe mixed with the liquor from the washer 5. The shaft 2 rotates at appropriate speed and the rotating arms I keep the mass agitated. The paddle 9 on the rotating arms I lift an amount of cellulose acetate and because of the angle of the face of the paddle 9, the lifted cellulose acetate slides down the opening into the chute 4 which conducts it to the washer I.

In the washer 5, fresh water is fed by pipe 22 and this water fills all the compartments, flowing over the lower edges ll of the partitions ll until the liquor outlet 22 is reached. The cellulose acetate from the drainer 2 passes into the first compartment ll, where it is washed with the liquor therein, and is then caused to move gradually by the rotating paddles l9 towards the partition l5. In rotating, the wedged-shaped paddles 2| lift a portion of the cellulose acetate material above the liquid level, and during the time when the cellulose acetate is passing from the liquid level to the upper edge of the higher portion ll of the partition, the free liquor drains down through the space between the paddle 2| and the partition l5. Upon reaching the upper edge of the partition ll, because of the angle the face of the paddle makes with the horizontal and the angle of the upper edge of the partition, the cellulose acetate easily slides down into the next compartment l5. This operation is repeated in each of the compartments, the cellulose acetate being washed with progressively fresher liquor, while the more concentrated liquor comes in contact with cellulose acetate that has the larger content of acid. By this counter-current principle, the cellulose acetate leaving the washer I through the chute 24 is substantially'free of acid. while the liquor leaving thepipe 22 is of relatively high concentration.

Theshaft2 isrotatedatsuchspeedthatthe cellulose acetate is sublectedto the required degree of washing before it leaves the washer, the time required for the cellulose acetate to pal through the washer being from 2 to 24 hours.

The acid liquor from the pipe 22 of the washer may be mixed with the drained acid liquor collected in receptacle |2 fromthe drainer 2, and this mixture may be treated solvents, by distillation, or neutralization with alkaline material, to recover concentrated acetic acid or other desired products.

While this invention has been described specifically in connection with the draining and washing of cellulose acetate that has been precipitated from its solution in acetic acid, it is adapted for the treatment of any kind of solid material in more or less divided form with any liquid. Thus cellulose acetate or cellulose nitrate or other derivative of cellulose may be stabiliized in the washer 5, by causing the same to pass cells where it is first subjected to boiling water in. the first few cells, tion of hot mineral acid in other cells, and then to final washing in the last cells.

A machine of this type may also be used for treating cellulose acetate or other derivatives of cellulose with liquids, such as solutions of soluble salts of alkali or alkali earth metals, or solution! of aluminum salts, such as aluminum chloride. adapted to react chemically therewith or to exert any other desired action.

It is to be understood that the foregolnl detailed description is glvenmereiy by way of I]- lustration and that many variations may be made therein without departing from the spirit of my invention.

Having described my invention, what I claim and desire to secure by Letters Patent is:

1. Method of treating cellulose acetate in particle form with a liquid.comprising feeding the cellulose acetate to the first of a series of cells, causing the cellulose acetate to be moved scroll then to a very dilute loluby extraction with said cells, raising the cellulose acetate above the liquid level in the cells and permitting free liquid to drain therefrom, then passing the cellulose acetate to the next cell, while causing the liquid to pass in a counter-current direction through said cells.

, 2. Method oi. removing acid from cellulose acetate in particle iorm containing the same comprising passing the mixture of cellulose acetate and acid into a draining device, continuously passing the drained cellulose acetate to a washer comprising a series of cells, lifting the cellulose acetate above the liquid level in the cells and permitting free liquid to drain therefrom, then passing the material to the next cell, tvhile passing water in a counter-current direction through said cells.

3. In apparatus for treating solid material with a liquid in a continuous manner. the combination of a series of cells, means for feeding the material to the first of said'cells, a shaft passing through the cells and means ior rotating said shaft, arms attached to said shalt, means on said arms for propelling the material longitudinally of said cells. further arms on said shaft and carrying paddles adapted to raise the material above the liquid level and drop the same into the next cell, and means for passing liquid in a continuous manner through said cells.

4. In apparatus for treating solid material with a liquid in a continuous manner, the combination of an elongated vessel, partitions in said vessel dividing the same into a series 01' compartments, one side of the partitions being lower than the other,ashaitpassingthrough saidveaaeland means for rotating said shaft, arms attached to saidshaitmeansonsaidarmsiorpropellingthe material longitudinally of said cells, further arms on said shaft and ca rying paddles adapted to raise the material above the liquid level and drop thesameinto thenextcell, andmeansiorpassing liquid in a counter-cm'rent direction through said cells.

5. In apparatus for separating a liquid from a solid material in a continuous manner, the combination oi a drainer, means for introducing mas terial to the drainer, means for continuously removing the material irom the drainer to a washer, said washer comprising a series of cells, means for feeding the material to the first oi. said cells, ashattpassingthroughthecellsandmeansior rotating said shaft, arms attached to said shaft, means on said arms tor propelling the material longitudinally of said cells, i'urther arms on said shalt and carrying paddles adapted to raise the material above the liquid level and drop the same into the next cell, and means for passing liquid in a continuous manner through said cells. I 6. In a device for draining liquid from a mixture of solid material and liquid, the combination or a substantially closed vessel having a out. wardlg sloping bottom, spaced bars or slats tormlngatleastpartofsaidbottomarotatingshatt passing through said vessel, asitatins means attached to said shalt, arms attached to said shalt, and paddles on said arms adapted'to raise the solid material and drop the same into the outlet or the vessel. CLII'I ORD I. mm. 

